A DAC is used to convert a digital signal into an analog signal. An interpolation DAC steers current through differently-sized transistors in order to generate an output analog signal that corresponds to the input digital signal.
ATE refers to an automated, usually computer-driven, systems for testing devices, such as semiconductors, electronic circuits, and printed circuit board assemblies. A device tested by ATE is referred to as a device under test (DUT). ATEs use DACs in a variety of ways. For example, a DAC may convert a digital test signal to analog form for transmission to the DUT.